* [PATCH] perf/x86: Use kmalloc_array() in merge_attr()
@ 2016-09-04 9:00 SF Markus Elfring
2016-09-05 7:51 ` Peter Zijlstra
0 siblings, 1 reply; 5+ messages in thread
From: SF Markus Elfring @ 2016-09-04 9:00 UTC (permalink / raw)
To: x86, Alexander Shishkin, Arnaldo Carvalho de Melo,
H. Peter Anvin, Ingo Molnar, Peter Zijlstra, Thomas Gleixner
Cc: LKML, kernel-janitors, Julia Lawall, Paolo Bonzini
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 4 Sep 2016 10:45:20 +0200
* A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "kmalloc_array".
This issue was detected by using the Coccinelle software.
* Replace the specification of a data structure by a pointer dereference
to make the corresponding size determination a bit safer according to
the Linux coding style convention.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
arch/x86/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 18a1acf..f7f3578 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1618,7 +1618,7 @@ __init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
j++;
j++;
- new = kmalloc(sizeof(struct attribute *) * j, GFP_KERNEL);
+ new = kmalloc_array(j, sizeof(*new), GFP_KERNEL);
if (!new)
return NULL;
--
2.9.3
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] perf/x86: Use kmalloc_array() in merge_attr()
2016-09-04 9:00 [PATCH] perf/x86: Use kmalloc_array() in merge_attr() SF Markus Elfring
@ 2016-09-05 7:51 ` Peter Zijlstra
2016-09-14 16:40 ` SF Markus Elfring
0 siblings, 1 reply; 5+ messages in thread
From: Peter Zijlstra @ 2016-09-05 7:51 UTC (permalink / raw)
To: SF Markus Elfring
Cc: x86, Alexander Shishkin, Arnaldo Carvalho de Melo,
H. Peter Anvin, Ingo Molnar, Thomas Gleixner, LKML,
kernel-janitors, Julia Lawall, Paolo Bonzini
On Sun, Sep 04, 2016 at 11:00:15AM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 4 Sep 2016 10:45:20 +0200
>
> * A multiplication for the size determination of a memory allocation
> indicated that an array data structure should be processed.
> Thus use the corresponding function "kmalloc_array".
>
> This issue was detected by using the Coccinelle software.
>
> * Replace the specification of a data structure by a pointer dereference
> to make the corresponding size determination a bit safer according to
> the Linux coding style convention.
Why!?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: perf/x86: Use kmalloc_array() in merge_attr()
2016-09-05 7:51 ` Peter Zijlstra
@ 2016-09-14 16:40 ` SF Markus Elfring
2016-09-14 17:04 ` Peter Zijlstra
0 siblings, 1 reply; 5+ messages in thread
From: SF Markus Elfring @ 2016-09-14 16:40 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, Alexander Shishkin, Arnaldo Carvalho de Melo,
H. Peter Anvin, Ingo Molnar, Thomas Gleixner, LKML,
kernel-janitors, Julia Lawall
>> * A multiplication for the size determination of a memory allocation
>> indicated that an array data structure should be processed.
>> Thus use the corresponding function "kmalloc_array".
>>
>> This issue was detected by using the Coccinelle software.
>>
>> * Replace the specification of a data structure by a pointer dereference
>> to make the corresponding size determination a bit safer according to
>> the Linux coding style convention.
>
> Why!?
How do you think about an information like the following from
the well-known script "checkpatch.pl"?
WARNING: Prefer kmalloc_array over kmalloc with multiply
Would you like to suggest any more constraints for this kind of
software refactoring?
Regards,
Markus
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: perf/x86: Use kmalloc_array() in merge_attr()
2016-09-14 16:40 ` SF Markus Elfring
@ 2016-09-14 17:04 ` Peter Zijlstra
2016-09-14 17:38 ` SF Markus Elfring
0 siblings, 1 reply; 5+ messages in thread
From: Peter Zijlstra @ 2016-09-14 17:04 UTC (permalink / raw)
To: SF Markus Elfring
Cc: x86, Alexander Shishkin, Arnaldo Carvalho de Melo,
H. Peter Anvin, Ingo Molnar, Thomas Gleixner, LKML,
kernel-janitors, Julia Lawall
On Wed, Sep 14, 2016 at 06:40:32PM +0200, SF Markus Elfring wrote:
>
> Would you like to suggest any more constraints for this kind of
> software refactoring?
Yes, don't do it. If you're writing new code by all means, do whatever
you feel, but don't go changing code just because checkpatch.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: perf/x86: Use kmalloc_array() in merge_attr()
2016-09-14 17:04 ` Peter Zijlstra
@ 2016-09-14 17:38 ` SF Markus Elfring
0 siblings, 0 replies; 5+ messages in thread
From: SF Markus Elfring @ 2016-09-14 17:38 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, Alexander Shishkin, Arnaldo Carvalho de Melo,
H. Peter Anvin, Ingo Molnar, Thomas Gleixner, LKML,
kernel-janitors, Julia Lawall
>> Would you like to suggest any more constraints for this kind of
>> software refactoring?
>
> Yes, don't do it.
I am bit surprised by this feedback.
> If you're writing new code by all means, do whatever you feel,
Could you accept related software updates then?
> but don't go changing code just because checkpatch.
Why is this not a valid reason for you?
How useful can properties that are provided by a function like
kmalloc_array() be also for software modules which you care about?
Do you find any other software improvements more worthwhile?
Regards,
Markus
^ permalink raw reply [flat|nested] 5+ messages in thread
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2016-09-04 9:00 [PATCH] perf/x86: Use kmalloc_array() in merge_attr() SF Markus Elfring
2016-09-05 7:51 ` Peter Zijlstra
2016-09-14 16:40 ` SF Markus Elfring
2016-09-14 17:04 ` Peter Zijlstra
2016-09-14 17:38 ` SF Markus Elfring
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